To kick off an event, you generally need to do something in the service. Here, we'll make a POST /folders request to create a new folder, and expect to get a notification: HTTP Headers: Authorization- User <user secret>, Organization ...

All instances containing a Callback Notification Signature Key will include the Elements-Webhook-Signature header field. The value of this field will contain a unique SHA256 hash that corresponds to the event (e.g., sha256=jHdbRx5EZAsOfTwAPJOGkN...